Bolts and bolt and nut fasteners

ABSTRACT

A bolt includes a shank having a first end, a second end, a first external thread proximate to the first end, and a second external thread proximate to the second end. The first external thread twists in a first direction, the second external thread twists in a second direction, and the first direction is different from the second direction. The first external thread includes a minor diameter, the second external thread includes a major diameter, and the minor diameter of the first external thread is greater than the major diameter of the second external thread.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 63/205,671, filed 4 Jan. 2021, incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to bolts, bolt and nutfasteners, and bolted joints.

BACKGROUND OF THE INVENTION

In many manufactured products, it is essential to join two or moreelements or surfaces together. Bolted joints are useful for this whenthe elements require periodic disassembly and assembly withoutdestroying the joint.

Bolted joints include fasteners that capture and join other parts, andare secured by mating screw threads. A bolted joint is either a softjoint or a hard joint. A soft-bolted joint is when the hardness of atleast one of the elements is below 30 RC. A hard-bolted joint is whenthe hardness of all the elements is greater than 30 RC. A bolted jointmay use a through-hole or a tapped hole. A through-hole or stud jointrelies on parts joined together using a stud. A tapped hole or screwjoint relies on parts joined together using a threaded hole and athreaded fastener.

The objective of a bolted joint is to maintain joint cohesiveness,whether a tension joint or a shear joint. The axial forces exerted bythe parts of a tension joint try to separate the joint. Accordingly, thebolt of a tension joint must serve as a clamp to hold the partstogether. The shear forces exerted by the elements of a shear joint tryto separate the joint. Accordingly, the bolt of a shear joint must serveas a pin to keep the parts stationary.

A standard bolt is a longitudinally straight shank including a firstend, a second end, a head proximate to the first end, and an externalthread. The external thread between the first and second ends isconfigured to thread on an internal thread of a tapped nut,through-hole, or blind hole. A standard bolted joint includes theinternal thread exerting an axial clamping force and the bolt's shankacting as a dowel, pinning the joint against lateral shear forces. Thelocking method of the bolted joint includes the internal thread of thenut, opening, or blind bore on the external thread of the bolt.Rotational engagement of the internal thread over and on the externalthread creates axial clamping.

Vibration and prevailing torque capable of inducing relative movementbetween bolted structures can loosen bolted joints by unwinding thebolt's external thread from the applied internal thread. While skilledartisans have developed locknuts, jam nuts, lock washers, andthread-locking fluid to resist loosening, existing methods are notentirely satisfactory, unreliable, and, in many implementations,impracticable, necessitating continued improvement in the art.

SUMMARY OF THE INVENTION

According to the invention, a bolt includes a shank including a firstend, a second end configured with an enlarged head for bolt-turnpurposes, a first external thread proximate to the first end, and asecond external thread proximate to the second end. The first externalthread twists in a first direction, and the second external threadtwists in a second direction different from the first direction. Thefirst external thread includes a first pitch, the second external threadincludes a second pitch, and the first pitch is different from thesecond pitch. A body of the shank separates the first external threadfrom the second external thread. The body of the shank is unthreaded.The first external thread includes a minor diameter, the second externalthread includes a major diameter, and the minor diameter of the firstexternal thread is greater than the major diameter of the secondexternal thread. A nut includes a threaded hole including an internalthread having a minor diameter and a pitch. The pitch of the nut isequal to the first pitch, the minor diameter of the internal thread isgreater than the major diameter of the second external thread, and theinternal thread corresponds to and is configured to thread on the firstexternal thread.

According to the invention, a bolt includes a shank including a firstend, a second end, an enlarged head proximate to the first end, theenlarged head configured with a first external thread and a radialbearing surface between the shank and the first external thread andfacing the second end, and a second external thread proximate to thesecond end. The first external thread twists in a first direction andincludes a minor diameter, and the second external thread twists in asecond direction different from the first direction and includes a majordiameter less than the minor diameter. The first external threadincludes a first pitch, the second external thread includes a secondpitch, and the first pitch is equal to the second pitch. The enlargedhead is configured with one of a socket and a key for bolt-turnpurposes. A body of the shank separates the first external thread fromthe second external thread. The body of the shank is unthreaded. A nutincludes a threaded hole including an internal thread having a minordiameter and a pitch. The pitch of the nut is equal to both the firstpitch and the second pitch. The minor diameter of the internal threadgreater than the major diameter of the second external thread, and theinternal thread corresponds to and is configured to thread on the firstexternal thread.

According to the invention, a bolt includes a shank including a firstend, a second end, a first external thread proximate to the first end,and a second external thread proximate to the second end. The firstexternal thread twists in a first direction and includes a first pitchand a minor diameter. The second external thread twists in a seconddirection different from the first direction and includes a second pitchequal to the first pitch and a major diameter less than the minordiameter. A nut includes a threaded hole including an internal threadhaving a minor diameter and a pitch. The pitch of the nut is equal toboth the first pitch and the second pitch, the minor diameter of theinternal thread is greater than the major diameter of the secondexternal thread, and the internal thread corresponds to and isconfigured to thread on the first external thread. A body of the shankseparates the first external thread from the second external thread. Thebody of the shank is unthreaded.

According to the invention, a fastener includes a bolt, an anchor nut,and a locknut. The bolt includes a shank having a first end, a secondend, and a first external thread proximate to the first end andincluding a major diameter. The anchor nut includes a head, a secondexternal thread including a minor diameter greater than the majordiameter, and a first hole including a first internal thread configuredto thread on the first external thread. The locknut includes a secondhole including a second internal thread configured to thread on thesecond external thread. The first external thread and the first internalthread twist in a first direction, and the second external thread andthe second internal thread twist in a second direction different fromthe first direction. The first external thread, the second externalthread, the first internal thread, and the second internal threadincluding identical pitches. An enlarged head is adjacent to the secondend. The anchor nut additionally includes a first open end, a secondopen end, the first hole extends through the anchor nut from the firstopen end to the second open end, the head is proximate to the first openend, and the second external thread is proximate to the second open end.The anchor nut has a radial bearing surface between the head and thesecond external thread. The locknut includes a first or inner side, asecond or outer side, a first dimension from the first side to thesecond side, the second hole extends through the locknut from the firstside to the second side, and the anchor nut includes a second dimensionfrom the radial bearing surface to the second open end. In oneembodiment, the second dimension is less than the first dimension, thefirst internal thread extends from the first open end to a runoutbetween the first open and the second open end, and the first hole isunthreaded from the runout to the second open end. In anotherembodiment, the second dimension is greater than the first dimension,and the first internal thread extends from the first open end to thesecond open end.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific objects and advantages of the invention will be readilyapparent to those skilled in the art from the following detaileddescription of illustrative embodiments thereof, taken in conjunctionwith the drawings in which:

FIGS. 1 and 2 are perspective views of a fastener constructed andarranged according to the invention, the fastener including a bolt and anut shown disassembled;

FIG. 3 is a central longitudinal section view along line 3-3 of FIG. 2 ;

FIGS. 4 and 5 are perspective views of the fastener of FIGS. 1 and 2showing the bolt and the nut assembled;

FIG. 6 is a central longitudinal section view along line 6-6 of FIG. 5 ;

FIG. 7 is a view corresponding to FIG. 6 illustrating the fastener inuse;

FIG. 8 is a perspective view of another embodiment of a fastenerconstructed and arranged according to the invention;

FIG. 9 is a central longitudinal section view along line 9-9 of FIG. 8 ;

FIG. 10 is a view corresponding to FIG. 9 illustrating the fastener inuse;

FIGS. 11 and 12 are perspective views of a yet another embodiment of afastener constructed and arranged according to the invention, thefastener including a bolt and a nut shown disassembled;

FIG. 13 is a side elevation view of the fastener of FIGS. 11 and 12showing the bolt and the nut assembled;

FIGS. 14 and 15 are perspective views of the fastener of FIGS. 11 and 12shown assembled;

FIG. 16 is a central longitudinal section view along line 16-16 of FIG.15 ;

FIG. 17 is a view corresponding to FIG. 16 illustrating the fastener inuse;

FIG. 18 is perspective view of still another embodiment of a fastenerconstructed and arranged according to the invention;

FIG. 19 is a perspective view of yet still another embodiment of afastener constructed and arranged according to the invention, thefastener including a bolt, an anchor nut, and a locknut showndisassembled;

FIG. 20 is a central longitudinal section view of the bolt along line20-20 of FIG. 19 ;

FIG. 21 is a central longitudinal section of the anchor nut and thelocknut along line 20-20 of FIG. 19

FIG. 22 is a side elevation view of the anchor nut and the locknut ofFIG. 19 shown assembled to form an anchor nut assembly;

FIG. 23 is a central longitudinal section view along line 23-23 of FIG.22 ;

FIGS. 24 and 25 are perspective views of the fastener of FIG. 19 showingthe bolt, the anchor nut, and the locknut assembled;

FIG. 26 is a side elevation view of the embodiment of FIGS. 24 and 25 ;

FIG. 27 is a section view along line 27-27 of FIG. 26 ;

FIG. 28 is a view corresponding to FIG. 27 illustrating the fastener inuse;

FIG. 29 is a perspective view of still another embodiment of a fastenerconstructed and arranged according to the invention and showndisassembled, the fastener including a bolt, an anchor nut, and alocknut;

FIG. 30 is a central longitudinal section view of the anchor nut and thelocknut of FIG. 29 shown assembled to form an anchor nut assembly; and

FIG. 31 is a central longitudinal section view of fastener of FIG. 29showing the bolt, the anchor nut, and the locknut assembled and in use.

DETAILED DESCRIPTION

Improved bolts, bolt and nut fasteners, and bolted joints are disclosed.

I

Turning now to the drawings, like reference characters indicatingcorresponding elements throughout the several views, FIGS. 1 and 2illustrate fastener 50 constructed and arranged according to theinvention. Fastener 50 is useful in forming bolted joints and includesbolt 52 and nut 54 configured to be repeatedly and quickly assembled anddisassembled. All diameters referenced throughout this specificationrelated to fastener 50 are constant.

In FIGS. 1, 2, and 3 , bolt 52 includes longitudinally straightcylindrical shank 60 extending from proximal end 62 configured withenlarged head 100 to distal end 64, and external threads 70 and 80 oneither side of unthreaded body 90, including a diameter 92 in FIG. 3 .Head 100 has wrench flats 102, six in this example, for bolt-turnpurposes, and underside 104. Shank 60 extends outwardly to distal end 64from proximal end 62 affixed centrally to underside 104 of head 100.Radial bearing surface or radius 104A of underside 232 radiatesoutwardly from body 90.

In FIGS. 1-3 , external thread 70 near head 100 twists in a left-handdirection and is exemplary of a standard left-handed external thread. InFIG. 3 , external thread 70 includes thread length 71 extending fromclosely adjacent to proximal end 62 and radial bearing surface 104 torunout 72 on a proximal side of body 70, minor diameter 73, majordiameter 74, and pitch 75, the distance between adjacent peaks or crestsof the thread. Minor diameter 73 occurs at the roots of external thread70, and major diameter 74 occurs at the crests of external thread 70.

In FIGS. 1-3 , external thread 80 near distal end 64 twists in aright-hand direction opposite to the left-hand direction of externalthread 70 and is exemplary of a standard right-handed external thread.In FIG. 3 , external thread 80 includes thread length 81 extending fromdistal end 64 to runout 82 on a distal side of body 70, minor diameter83, major diameter 84, and pitch 85, the distance between adjacent peaksor crests of the thread. Minor diameter 83 occurs at the roots ofexternal thread 80. Major diameter 84 occurs at the crests of externalthread 80.

External threads 70 and 80 twist in opposite directions, as described.Accordingly, external threads 70 and 80 are counter-threads configuredto threadedly receive counter-rotating internally-threaded elements.External thread 70 is the proximal left-handed external thread of bolt52 near or otherwise proximate to radial bearing surface 104 of head100. External thread 80 opposite to external thread 70 is the distalright-handed external thread proximate to distal end 64. Thread length81 of external thread 80 is greater than thread length 71 of externalthread 70 and less than grip length 94 of body 90 extending from runout72 to runout 82. Grip length 94 is the length of the unthreaded portionof shank 60, namely, body 90. Grip length 94 is the free length of bolt52 that is stretched under tension. Pitch 75 is slightly larger thanpitch 85, and this can be reversed in an alternate embodiment. Pitches75 and 85 can be the same in a specific embodiment. Minor diameter 73 ofexternal thread 70 is larger than diameter 92 of body 90 and majordiameter 84 of external thread 80. Accordingly, external thread 70 isthe major external thread of bolt 52, and external thread 80 is theminor external thread of bolt 52.

In FIGS. 1 and 2 , nut 54 and is an annular block configured with athreaded hole 111, including internal thread 112. Threaded hole 111extends through nut 54 from an inner side 54A of nut 54 to an outer side54B of nut 54. Inner and outer sides 54A and 54B of nut 54 are radialbearing surfaces. Nut 54 has a thickness from inner side 54A to outerside 54B. Internal thread 112 runs along the inside of nut 54 betweenthe opposed inner and outer sides 54A and 54B and twists in the sameleft-hand direction as external thread 70. In FIG. 6 , internal thread112 includes minor diameter 113, major diameter 114, and pitch 115, thedistance between adjacent peaks or crests of the thread. Minor diameter113 occurs at the crests of internal thread 112, and major diameter 114occurs at the roots of internal thread 112. Pitches 75 and 115 areidentical. Minor diameter 113 of internal thread 112 is greater thandiameter 92 of body 90 and major diameter 84 of external thread 80.Minor and major diameters 113 and 114 of internal thread 112 correspondto the respective minor and major diameters 73 and 74 of external thread70. External thread 70 and internal thread 112 correspond by being thesame size and having identical pitches.

Since minor diameter 113 of internal thread 112 is greater than majordiameter 84 of external thread 80 and diameter 92 of body 90, threadedhole 111 is configured to receive therethrough in a direction from outerside 54B of body 54 to inner side 54A of body 54 distal end 64 shank 60and sequentially pass over external thread 80 and body 90 to runout 72of external thread 70 without interference from external thread 80.Since pitch 115 of internal thread 112 and pitch 75 of external thread70 are the same, minor and major diameters 113 and 114 of internalthread 112 correspond to the respective minor and major diameters 73 and74 of external thread 70, internal thread 112 twists in the sameleft-hand direction as external thread 70, and internal and externalthreads 112 and 70 are correspondingly sized, internal thread 112corresponds to and is configured to thread rotationally over and onexternal thread 70 from runout 72 in the direction of arrow B in FIGS.4-6 when rotated in the direction of arrow A and off external thread 70from runout 72 in the direction of arrow D when rotated in the directionof arrow C. Accordingly, internal thread 112 corresponds to and isconfigured to thread over and on external thread 70 but not on externalthread 80.

Nut 54 advances toward underside 104 of head 100 and away from distalend 64 in the direction of arrow B in FIGS. 4-6 , when nut is 54 isrotated over and on external thread 70 in a counterclockwise directionof arrow A in FIGS. 4 and 5 when seen from the point of view facingdistal end 64 on the central longitudinal axis of shank 60. Nut 54 issuitably sized to extend entirely over external thread 70 from outerside 54B of nut 54 tightened directly against underside 104 of head 100to inner side 54A of nut 54 proximate to body 90 outboard of externalthread 70 in the assembled fastener 50, when nut 54 is tighteneddirectly against underside 104 of head 100 by rotating it in thedirection of arrow A tightly against underside 104 of head 100. Nut 54withdraws from underside 104 of head 100 and away from distal end 64 inthe direction of arrow D in FIGS. 4-6 when nut 54 is rotated on externalthread 70 in a clockwise direction of arrow C in FIGS. 4 and 5 when seenfrom the point of view facing distal end 64 on the central longitudinalaxis of shank 60. Once nut 54 is free from external thread 70, the usermay withdraw nut 54 from bolt 52 in the direction of arrow D to separatenut 54 from bolt 52. The described process for assembling anddisassembling fastener 50 is repeatable is needed. In FIGS. 1, 2, 4, and5 , nut 54 has parallel and circumferentially spaced-apart wrenchgrooves 118 for nut-turn purposes. Repeated reference to the describeddirections of arrows A, B, C, and D is made throughout thisspecification with the various embodiments disclosed herein and used inthe various figures for reference purposes.

The assembled fastener 50 in FIGS. 4-6 is useful in forming boltedjoints, such as bolted joint 120 in FIG. 7 . FIG. 7 illustrates twomembers 122 and 124 secured together by assembled fastener 50. Members122 and 124, metal plates in this example, have registered through bores126 and 128, respectively. Bore 128 is tapped with internal thread 130,and is exemplary of a tapped or internally threaded bore 128. Thread 130is a right-hand thread and corresponds to external thread 80, enablingit to thread conventionally on external thread 80 when bolt 52 is turnedin the direction of arrow A.

A user forms bolted joint 120 with fastener 50 to secure members 122 and124 together by inserting bolt 60 distal end 64 first into and throughbore 126 to bore 128. He threads internal thread 130 over and onexternal thread 80 and advances bolt 52 in the direction of arrow D byrotating bolt 52 in the direction of arrow A until inner side 54A of nut54 tightens against member 122. Bolt length 94, the free length of bolt52 that is stretched under tension, extends through bore 126 of member122 to external thread 80 threaded to internally threaded bore 128. Healternately rotates nut 54 and bolt 52 in the direction of arrow A whileholding the other one stationary. This alternately tightens outer side54B of nut 54 against underside 104 of head 100 and inner side 54A ofnut 54 against member 122 until the desired tension is achieved, tightlyclamping member 122 between member 124 and inner side 54A of nut 54 andtightly clamping nut 54 between underside 104 of head 100 and member122. Since rotation of bolt 52 in the direction of arrow A urges bolt 52in the direction of arrow D and rotation of nut 54 relative to bolt 52in the same direction of arrow A urges nut 54 in the opposite directionof arrow B, nut 54 with its outer side 54B tightened directly againstunderside 104 of head 100 and its inner side 54A tightened directlyagainst member 122 disables bolt 52 from loosening by rotating in thedirection of arrow C. Accordingly, nut 54 serves as a locknutcounter-rotated relative to bolt 52 aggressively disabling bolt 52 fromloosening by rotating in the direction of arrow C. Fastener 50 securingbolted joint 120 is surprisingly strong and aggressive and resistant toaxial failure, shear failure, and loosening in response to vibrationaland prevailing torsional forces. Nut 54 additionally serves todistribute the load of fastener 50. The user need only reverse thisoperation to release bolted joint 120 and withdraw fastener 50. Theskilled artisan will readily appreciate that handedness of the threadsdescribed in conjunction with fastener 50 can be reversed in alternateembodiments.

The assembled fastener 50 in FIGS. 4-6 is also useful with a nut 140 andwasher 148 in FIG. 8 to form an alternate embodiment of a fastener 50′useful in forming bolted joint 160 in FIG. 10 , including members 162and 164 secured together by fastener 50′. Fastener 50′ is the assemblyof bolt 52, nut 54, nut 140, and washer 148. Members 162 and 164 in FIG.10 , metal plates in this example, have registered through bores 166 and168, respectively. FIG. 9 is a section view along 9-9 of fastener 50′ ofFIG. 8 illustrating the assembly of bolt 52, nut 54, nut 140, and washer148. The assembly of bolt 52 and nut 54 in FIGS. 9 and 10 incorporatethe reference characters as fastener 50 in FIGS. 6 and 7 .

Nut 140 is an annular block configured with a threaded hole 141,including internal thread 142. Threaded hole 141 extends through nut 140from an inner side 140A of nut 140 to an outer side 140B of nut 140.Inner and outer sides 140A and 140B of nut 140 are radial bearingsurfaces. Internal thread 142 runs along the inside of nut 140 betweenthe opposed inner and outer sides 140A and 140B and twists in the sameright-hand direction as external thread 80. Internal thread 142 includesminor diameter 143, major diameter 144, and pitch 145, the distancebetween adjacent peaks or crests of the thread. Minor diameter 143occurs at the crests of internal thread 142, and major diameter 144occurs at the roots of internal thread 142. Pitch 145 is identical topitch 85. Minor and major diameters 143 and 144 of internal thread 142correspond to the respective minor and major diameters 83 and 84 ofexternal thread 80. Since pitch 145 of internal thread 142 and pitch 85of external thread 80 are the same, minor and major diameters 143 and114 of internal thread 142 correspond to the respective minor and majordiameters 83 and 84 of external thread 80, internal thread 142 twists inthe same right-hand direction as external thread 80, and internal andexternal threads 142 and 80 are correspondingly sized, internal thread142 corresponds to and is configured to thread rotationally over and onexternal thread 80 from distal end 64 and off external thread 80 fromdistal end 64. External thread 80 and internal thread 142 correspond bybeing the same size and having identical pitches.

In FIG. 10 , a user forms bolted joint 160 with fastener to securemembers 162 and 164 together by inserting bolt 60 distal end 64 firstinto and through bore 166 to bore 168 to bring inner side 54A of nut 54against member 162 on one side of the bolted joint 160 and extendexternal thread 80 outwardly from bore 168 to distal end 64 on theopposite side of the bolted joint 160. The user locates washer 148 overexternal thread 80. He threads internal thread 142 on external thread 80by inserting distal end 64 into threaded hole 141 and rotating nut 140in the direction of arrow C. This advances nut 140 in the direction ofarrow B until nut 140 is tightened directly against washer 148 initiallyclamped between outer side 140B of nut 54 and member 164. Bolt length 94extends through bores 166 and 168 to external thread 80, extendingoutwardly from bore 166 to distal end 64. He either holds nut 140 fromrotating or urges rotation of nut 140 in the direction of arrow C and atthe same time alternately rotates nut 54 and bolt 52 in the direction ofarrow A while holding the other one stationary as in joint 120. Asdescribed above, this alternately tightens outer side 54B of nut 54against underside 104 of head 100 and inner side 54A of nut 54 againstmember 122 until the desired tension is achieved, tightly clampingmembers 162 and 164 between washer 148 and inner side 54A of nut 54 andtightly clamping nut 54 between underside 104 of head 100 and member162. Nut 54 serves as a locknut counter-rotated relative to bolt 52aggressively disabling bolt 52 from loosening by rotating in thedirection of arrow C in bolted joint 160 as in bolted joint 120.Fastener 50′ securing bolted joint 160 is surprisingly strong andaggressive and resistant to axial failure, shear failure, and looseningin response to vibrational and prevailing torsional forces. Nut 54serves to distribute the load of fastener 50′ as described above inbolted joint 120. The user need only reverse this operation to releasebolted joint 160 and withdraw fastener 50′. The skilled artisan willreadily appreciate that handedness of the threads described inconjunction with fastener 50′ can be reversed in alternate embodiments.

II

FIGS. 11-13 illustrate another embodiment of a fastener 180 constructedand arranged according to the invention. Fastener 180 is useful informing bolted joints and includes bolt 182 and nut 184 is configured tobe repeatedly and quickly assembled and disassembled. All diametersreferenced throughout this specification related to fastener 180 areconstant.

Bolt 182 includes longitudinally straight cylindrical shank 190extending from proximal end 192 configured with enlarged head 230 todistal end 194. External threads 200 and 210 are on either side ofunthreaded body 220, including a diameter 222 in FIG. 13 . Head 230, anenlarged cylindrical body, includes underside 232 and opposed outer side234. Head 230 is circumferentially enlarged relative to shank 190 and isexternally threaded with thread 200 extending between underside 232 andouter side 234. Shank 190 extends outwardly to distal end 194 fromproximal end 192 affixed centrally to underside 232 of head 230. Radialbearing surface or radius 232A of underside 232 radiates outwardly frombody 220 to external thread 200. In FIG. 12 , blind keyway 236 forbolt-turn purposes extends into head 230 centrally from outer side 234.All diameters referenced related to fastener 180 are constant.

In FIGS. 11-13 , external thread 200 near proximal extremity 192 twistsin a left-hand direction and is exemplary of a standard left-handedexternal thread. In FIG. 13 , external thread 200 includes thread length201 extending between underside 232 adjacent to proximal end 192 andouter side 234, minor diameter 203, major diameter 204, and pitch 205,the distance between adjacent peaks or crests of the thread. Minordiameter 203 occurs at the roots of external thread 200, and majordiameter 204 occurs at the crests of external thread 200.

External thread 210 near distal end 194 twists in a right-hand directionopposite to the left-hand direction of external thread 200 and isexemplary of a standard right-handed external thread. In FIG. 13 ,external thread 200 includes thread length 211 extending from distal end194 to runout 212, minor diameter 213, major diameter 214, and pitch215, the distance between adjacent peaks or crests of the thread. Minordiameter 213 occurs at the roots of external thread 210. Major diameter214 occurs at the crests of external thread 200.

External threads 200 and 210 twist in opposite directions, as described.Accordingly, external threads 200 and 210 are counter-threads configuredto threadedly receive counter-rotating internally-threaded elements.External thread 200 is the proximal left-handed external thread of bolt182 proximate to proximal end 192. External thread 210 opposite toexternal thread 200 is the distal right-handed external thread of bolt182 proximate to distal end 194. Thread length 211 of external thread210 is greater than thread length 201 of external thread 200 and lessthan grip length 224 of body 220 extending from underside 232 ofexternally-threaded head 230 to runout 212. Grip length 224, the lengthof the unthreaded portion of shank 190, namely, body 220, is the freelength of bolt 182 that is stretched under tension. Pitches 205 and 215are identical. Minor diameter 203 of external thread 200 is larger thandiameter 222 of body 190 and major diameter 214 of external thread 210.Accordingly, external thread 200 is the major external thread of bolt182, and external thread 210 is the minor external thread of bolt 182.External threads 200 and 210 are the same size and have identicalpitches.

In FIGS. 11 and 12 , nut 184 is an annular block configured with athreaded hole 240, including internal thread 242. Threaded hole 240extends through nut 184 from an inner side 184A of nut 184 to an outerside 184B of nut 184. Inner and outer sides 184A and 184B of nut 184 areradial bearing surfaces. Nut 184 has a thickness from inner side 184A toouter side 184B. Internal thread 142 runs along the inside of nut 184between the opposed inner and outer sides 184A and 184B and twists inthe same left-hand direction as external thread 200. In FIG. 16 ,internal thread 242 includes minor diameter 243, major diameter 244, andpitch 245, the distance between adjacent peaks or crests of the thread.Minor diameter 243 occurs at the crests of internal thread 242, andmajor diameter 244 occurs at the roots of internal thread 242. Pitches205, 215, and 245 are identical. Minor diameter 243 of internal thread242 is greater than diameter 222 of body 220 and major diameter 214 ofexternal thread 210. Minor and major diameters 243 and 244 of internalthread 242 correspond to the respective minor and major diameters 203and 204 of external thread 200. External thread 200 and internal thread242 correspond by being the same size and having identical pitches.Further, external threads 200 and 210 and internal thread 242 are thesame size and have identical pitches.

Since pitch 245 of internal thread 242 and pitch 205 of external thread200 are the same, minor and major diameters 243 and 244 of internalthread 242 correspond to the respective minor and major diameters 203and 204 of external thread 200, internal thread 242 twists in the sameleft-hand direction as external thread 200, and internal and externalthreads 242 and 200 are correspondingly sized, internal thread 242corresponds to and is configured to thread rotationally over and onexternal thread 200 and off external thread 200 from outer side 234 ofhead 230. Accordingly, internal thread 242 corresponds to and isconfigured to thread over and on external thread 200 but not on externalthread 210.

A user assembles fastener 180 in FIGS. 14, 15, and 16 by inserting bolt182 outer side 234 of head 230 first into threaded hole 241 from innerouter side 184A. He advances nut 184 in the direction of arrow D towardunderside 232 of head 230 by rotating nut 184 in the direction of arrowA over external thread 200. Nut 184 is suitably sized to extend entirelyover external thread 200 from inner side 184A of nut 184 proximate tounderside 232 of head 230 to outer side 184B of nut 184 proximate toouter side 234 of head 230, when internal thread 242 is completelythreaded over external thread 200 in the assembled fastener 180 in FIGS.14-16 . A user withdraws nut 184 from head 230 to disassemble fastener180 by reversing this operation. The described process for assemblingand disassembling fastener 180 is repeatable as needed. In FIGS. 11-15 ,nut 184 has parallel and circumferentially spaced-apart wrench grooves248 for nut-turn purposes.

The assembled fastener 180 in FIGS. 14-16 is useful in forming boltedjoint 250 in FIG. 17 . FIG. 17 illustrates two members 252 and 254secured together by assembled fastener 180. Members 252 and 254, metalplates in this example, have registered through bores 256 and 258,respectively. Bore 258 of member 254 is tapped with internal thread 260and is exemplary of a tapped or internally threaded bore 258. Thread 130corresponds to external thread 80, enabling it to thread conventionallyon external thread 80.

A user forms bolted joint 250 with fastener 180 in FIG. 17 to securemembers 252 and 254 together by inserting bolt 190 distal end 194 firstinto and through bore 256 to bore 258. He threads internal thread 260 onexternal thread 210 to advance bolt 182 in the direction of arrow D byrotating bolt 182 in the direction of arrow A until radial bearingsurface 232A of underside 232 of head 230 and inner side 184A of nut 184initially tighten against member 252. Bolt length 224 extends throughbore 256 of member 252 to external thread 210 threaded to internallythreaded bore 258. He alternately rotates nut 184 and bolt 182 in thedirection of arrow A while holding the other one stationary. Thisalternately tightens outer side 184B of nut 54 and radial bearingsurface 232A of underside 232 of head 230 against member 252 until thedesired tension is achieved, clamping member 252 between member 254 andboth inner side 184A of nut 54 and radial bearing surface 232A of head232. Since rotation of bolt 182 in the direction of arrow A urges bolt52 in the direction of arrow D and rotation of nut 184 relative to bolt182 in the same direction of arrow A urges nut 184 in the oppositedirection of arrow B, nut 184 serves as a locknut counter-rotatedrelative to head 230 of bolt 184 aggressively disabling bolt 182 fromloosening by rotating in the direction of arrow C. Radial bearingsurface 232A of head 230 additionally serves to distribute the load offastener 180 without the need for a washer, although one can use aseparate washer between radial bearing surface 232A and member 252 ifdesired. Since external threads 200 and 210 and internal thread 242 areidentically sized and have the same pitches, the threaded attachmentsare strong and resistant to stripping. Fastener 180 securing boltedjoint 250 is surprisingly strong and aggressive and resistant to axialfailure, shear failure, and loosening in response to vibrational andprevailing torsional forces. The user need only reverse this operationto release bolted joint 250 and withdraw fastener 180. Like fastener50′, the assembled fastener 180 in FIGS. 14-16 is also useful with a nutand washer to form an alternate embodiment of a fastener useful informing a bolted joint. The skilled artisan will readily appreciate thathandedness of the threads described in conjunction with fastener 180 canbe reversed in alternate embodiments.

Keyway 236 in FIGS. 12 and 15-17 is multifaced and exemplary of an Allenkeyway configured to accept an Allen key of a tool used to drive bolt182 rotationally. In an alternate embodiment of a fastener 180′ in FIG.18 that, in common with fastener 180, shares bolt 182 and nut 184, bolt182 is configured with a key 265 for bolt-turn purposes. Key 265 ismultifaced and exemplary of a standard Allen key configured to accept astandard Allen keyway of a tool used to drive bolt 182 rotationally. InFIG. 18 , key 265 for bolt-turn purposes extends outwardly from head 230centrally from outer side 234.

FIG. 19 illustrates yet another embodiment of a fastener 300 constructedand arranged according to the invention. Fastener 300 is useful informing bolted joints and includes bolt 302, anchor nut 304, and locknut306 configured to be repeatedly and quickly assembled and disassembled.Anchor nut 304 and locknut 306 are configured to be repeatedly assembledin FIGS. 22 and 23 to form an anchor nut assembly 345 and disassembledin FIGS. 19 and 21 independently from bolt 302. All diameters referencedthroughout this specification related to fastener 300 are constant.

In FIGS. 19 and 20 , bolt 302 includes longitudinally straightcylindrical shank 310 extending from proximal end 312 configured withenlarged lug or head 340 to distal end 314, external thread 320 andunthreaded body 330, including a diameter 332 in FIG. 20 . Shank 60extends outwardly to distal end 314 from proximal end 312 affixedcentrally to head 240 configured to be anchored in a counterbore.External thread 320 twists in a right-hand direction and is exemplary ofa standard right-handed external thread. In FIG. 20 , external thread320 includes thread length 321 extending from distal end 314 to runout322 on a distal side of body 330, minor diameter 323, major diameter324, and pitch 325, the distance between adjacent peaks or crests of thethread. Minor diameter 323 occurs at the roots of external thread 320.Major diameter 324 occurs at the crests of external thread 320. Threadlength 321 of external thread 320 is less than grip length 334 of body330 extending from head 340 to runout 322. Grip length 334, the lengthof the unthreaded portion of shank 310, namely, body 330, is the freelength of bolt 302 that is stretched under tension.

In FIGS. 19 and 21 , anchor nut 304 is an annular block or bodyincluding open inner end 350, open outer end 352, flange 354, head 356,external thread 360, and hole 370 configured with internal thread 372.Hole 370 extends through anchor nut 304 from open inner end 350 to openouter end 352. Head 356 has wrench flats 358, six in this example, fornut-turn purposes, and extends from open inner end 350 to the inner orproximal side of flange 354. Flange 354 extends from its inner side athead 356 to its outer or distal side, including radial bearing surface354A. Radial bearing surface 354A faces external thread 360. Externalthread 360 extends between radial bearing surface 354A and outer end352, twists in a left-hand direction opposite to external thread 320 ofbolt 302, and is exemplary of a standard left-handed external thread.Head 356 and flange 354 together form an integrated flanged head ofanchor nut 304.

In FIG. 21 , left-handed external thread 360 includes thread length 361extending along the length of anchor nut 304 between radial bearingsurface 354A and outer end 352, minor diameter 363, major diameter 364,and pitch 365, the distance between adjacent peaks or crests of thethread. Minor diameter 363 occurs at the roots of external thread 360,and major diameter 364 occurs at the crests of external thread 360.External threads 320 and 360 twist in opposite directions, as described.Accordingly, external threads 320 and 360 are counter-threads configuredto threadedly receive counter-rotating internally-threaded elements.

Hole 370 extending through anchor nut 304 from open inner end 350 toopen outer end 352 in FIG. 21 has an internally threaded part 370A andcoaxial unthreaded part 370B. Internally threaded part 370A includesinternal thread 372 extending from open inner end 50 to runout 374 at anintermediate location of hole 370 between open inner end 350 and openouter end 352. Unthreaded part extends from runout 374 to open outer end352. Unthreaded part 370B has internal diameter 376 greater than majordiameter 324 of external thread 320 and diameter 332 of body 330 in FIG.20 .

In FIG. 21 , internal thread 372 runs along the inside of anchor nut 304between open inner end 350 and runout 374 and twists in the sameright-hand direction as external thread 320 of bolt 302 opposite to theleft-hand direction of external thread 360. Internal thread 372 includesminor diameter 383, major diameter 384, and pitch 385, the distancebetween adjacent peaks or crests of the thread. Minor diameter 383occurs at the crests of internal thread 372, and major diameter 384occurs at the roots of internal thread 372. Pitches 325, 365, and 385are identical. Minor and major diameters 383 and 384 of internal thread372 correspond to the respective minor and major diameters 323 and 324of external thread 320. External thread 320 and 360 and internal thread372 are the same size and have identical pitches.

Since diameter 376 of unthreaded part 370B of hole 370 of anchor nut 304is greater than major diameter 324 of external thread 320, unthreadedpart 370B of hole 370 is configured to receive therethrough in adirection from open outer end 352 distal end 324 of shank 310 and passover external thread 320 until external thread 320 at proximal end 314encounters runout 374. Since pitch 385 of internal thread 372 and pitch325 of external thread 320 are the same, minor and major diameters 383and 384 of internal thread 372 correspond to the respective minor andmajor diameters 323 and 324 of external thread 320, internal thread 372twists in the same right-hand direction as external thread 320, andinternal and external threads 372 and 320 are correspondingly sized,internal thread 372 corresponds to and is configured to threadrotationally over and on external thread 320 from runout 374 in FIG. 27and off external thread 320 from runout 374. Accordingly, internalthread 372 corresponds to and is configured to thread over and onexternal thread 320.

In FIGS. 19 and 21 , locknut 306 and is an annular block configured witha threaded hole 401, including internal thread 402. Threaded hole 401extends through locknut 306 from an inner or first side 306A of locknut306 to an outer or second side 306B of locknut 306. Inner and outersides 306A and 306B of locknut 306 are radial bearing surfaces. Nutlocknut 306 has a thickness 406 from inner side 306A to outer side 306B.In FIG. 21 , internal thread 402 runs along the inside of locknut 306between the opposed inner and outer sides 306A and 306B and twists inthe same left-hand direction as external thread 360 opposite to theright-hand hand direction of external thread 320 of bolt 302 andinternal thread 372 of anchor nut 304. Internal thread 402 includesminor diameter 403, major diameter 404, and pitch 405, the distancebetween adjacent peaks or crests of the thread. Minor diameter 403occurs at the crests of internal thread 402, and major diameter 404occurs at the roots of internal thread 402. Pitches 325, 365, 385, and405 are identical. Minor and major diameters 403 and 404 of internalthread 402 correspond to the respective minor and major diameters 363and 364 of external thread 360. External threads 320 and 360 andinternal threads 372 and 402 are the same size and have identicalpitches. In FIGS. 19, 22, and 24-26 , locknut 306 has parallel andcircumferentially spaced-apart wrench grooves 408 for nut-turn purposes.

Since pitch 405 of internal thread 402 and pitch 365 of external thread360 are the same, minor and major diameters 403 and 404 of internalthread 402 correspond to the respective minor and major diameters 363and 364 of external thread 360, internal thread 402 twists in the sameleft-hand direction as external thread 360, and internal and externalthreads 402 and 360 are correspondingly sized, internal thread 402corresponds to and is configured to thread rotationally over and onexternal thread 360 from open outer end 352 of anchor nut 304 in FIG. 23and off external thread 360 from open outer end 352. Accordingly,internal thread 402 corresponds to and is configured to thread over andon external thread 360 for assembling anchor nut 304 and locknut 306 toform anchor nut assembly 345 in FIGS. 22 and 23 . Internal threads 372and 402 twist in opposite directions, as described, internal thread 372in the same direction as external thread 320 and internal thread 402 inthe same direction as external thread 360. Accordingly, internal threads372 and 402 are counter-threads configured to threadedly receivecounter-rotating externally-threaded elements.

In FIG. 23 , a user assembles anchor nut assembly 345 by threadinginternal thread 402 over and on external thread 360. The user threadsinternal thread 402 over and on external thread 360 by inserting openouter end 352 of anchor nut 304 into threaded hole 401 from inner side306A and rotating locknut 306 in the direction of arrow C. This advanceslocknut 306 in the direction of arrow D until inner side 306A of locknut306 is tightened directly against radial bearing surface 354A of flange354. Locknut 306 is suitably sized to extend entirely over externalthread 360 from inner side 306A of locknut 306 tightened directlyagainst radial bearing surface 354A, shown also in FIG. 22 , to outerside 306B of locknut 306 outboard of open outer end 352 in the assemblyof anchor nut 304 and locknut 306 in FIG. 23 , when locknut 306 istightened directly against radial bearing surface 354A of flange 304 byrotating it in the direction of arrow C tightly against radial bearingsurface 354A of flange 304. Accordingly, the dimension of locknut 306from inner side 306A to outer side 306B, the thickness 406 of locknut306 from inner side 306A to outer side 306B in FIG. 21 , is greater thanthe dimension of anchor nut 304 from radial bearing surface 354A to openouter end 352, the thickness 366 of anchor nut 304 from radial bearingsurface 354A to open outer end 352 in FIG. 21 . Rotating locknut 306 inthe direction of arrow A opposite to the direction of arrow C withdrawslocknut 306 from radial bearing surface 354A in the direction of arrowB. Accordingly, a user need only reverse the operation threading locknut306 on anchor nut 304 to separate locknut 306 from anchor nut 304.Anchor nut 304 and locknut 306 may be repeatedly assembled anddisassembled as needed.

The assembly of bolt 302 and anchor nut assembly 345 forms fastener 300in FIGS. 24-27 . Referring to FIGS. 24-27 in relevant part, a userassembles anchor nut assembly 345 and bolt 302 by inserting bolt 302distal end 314 first into and through unthreaded part 370A of bore 370through open outer end 352 until external thread 320 at distal end 314encounters runout 374. He threads internal thread 372 on external thread320 and advances anchor nut assembly 345 in the direction of arrow D byrotating bolt 302 in the direction of arrow A until internal thread 372is threaded completely on external thread 320 in FIG. 27 . In FIG. 27 ,locknut 306 is between radial bearing surface 354A and head 340, innerside 306A is tightened directly against radial bearing surface 354A, andexternal thread 320 extends through unthreaded part 370B of hole 370from open outer end 352 to runout 374 and through threaded part 370A ofhole 370 from runout 374 to open inner end 350 and beyond open inner end350 to distal end 314 without interference from locknut 306 threaded onexternal thread 360 of anchor nut 304. External threads 320 and 360twist in opposite right and left directions, as described. Accordingly,anchor nut 304 threaded on bolt 302 and locknut 306 threaded on anchornut 306 are counter-rotated. Rotating anchor nut 304 equipped with itsattached locknut 306 in the direction of arrow A opposite to thedirection of arrow C withdraws anchor nut assembly 345 from externalthread 320 of bolt 302 in the direction of arrow D. Accordingly, a userneed only reverse the operation threading anchor nut 304 on bolt 302 toseparate anchor nut assembly 345 from bolt 302. Bolt 302 and anchor nutassembly 345 may be repeatedly assembled and disassembled as needed.

Fastener 300 is useful in forming bolted joint 410 in FIG. 28 ,including members 412 and 414 secured together by fastener 300, theassembly of bolt 302, anchor nut 304, and locknut 306. Members 412 and414, metal plates in this example, have registered through bores 416 and418, respectively. A user forms bolted joint 410 to secure members 412and 414 together by inserting bolt 302 free of anchor nut assembly 345distal end 314 first into and through bore 416 to bore 418 to seat head340 in bore's 416 counterbore 416A on one side of the bolted joint 410and extend external thread 320 outward from bore 418 to distal end 314on the opposite side of bolted joint 410. Head 340 and counterbore 416Aare correspondingly shaped. The user installs anchor nut assembly 345 onbolt 302 to assemble fastener 300 by inserting bolt 310 distal end 314first into and through unthreaded part 370A of bore 370 through openouter end 352 until external thread 320 at distal end 314 encountersrunout 374. He threads internal thread 372 on external thread 320 byrotating anchor nut 304 equipped with its installed locknut 306 in thedirection of arrow C. This advances anchor nut assembly 345 in thedirection of arrow B until internal thread 372 is threaded completely onexternal thread 320 between distal end 324 and member 414 and outer side306B of locknut 306 is tightened directly against member 414 initiallyclamping locknut 306 between radial bearing surface 354A of anchor nut304 and member 414. Since the dimension of locknut 306 from inner side306A to outer side 306B is greater than the dimension of anchor nut 304from radial bearing surface 354A to open outer end 352, open outer end352 is disabled from coming into direct contact against member 414. Boltlength 334 extends through bores 416 and 418 from head 340 incounterbore 416A to external thread 320, extending outward from bore 418to anchor nut assembly 345 and distal end 314 outboard of open inner end350. He alternately rotates anchor nut 304 and locknut 306 in thedirection of arrow C. This alternately tightens inner side 306A oflocknut 306 against radial bearing surface 354A and outer side 306B oflocknut 306 against member 414 until the desired tension is achieved,tightly clamping members 412 and 414 between head 340 anchored incounterbore 416A on one side of bolted joint 410 and outer side 306B oflocknut 306 on the opposite side of bolted joint 410 and tightlyclamping locknut 306 between radial bearing surface 354A tighteneddirectly against inner side 306A of locknut 306 and member 414 tighteneddirectly against outer side 306B of locknut 306. Locknut 306 tighteneddirectly against radial bearing surface 354A and member 414 serves itsfunction as a locknut counter-rotated relative to external thread 320 ofbolt 302 and internal thread 372 of anchor nut 304 aggressivelydisabling bolt 302 from loosening by rotating in the direction of arrowC. Since external threads 320 and 360 and internal threads 372 and 402are identically sized and have the same pitches, the threadedattachments are strong and resistant to stripping. Fastener 300 securingbolted joint 410 is surprisingly strong and aggressive and resistant toaxial failure, shear failure, and loosening in response to vibrationaland prevailing torsional forces. The user need only reverse thisoperation to release bolted joint 410 and withdraw fastener 300. Theskilled artisan will readily appreciate that handedness of the threadsdescribed in conjunction with fastener 300 can be reversed in alternateembodiments.

The thickness 406 of locknut 306 from inner side 306A to outer side 306Bin FIG. 21 is greater than the thickness 366 of anchor nut 304 fromradial bearing surface 354A to open outer end 352 in FIG. 21 . Thisdisables open outer end 352 from coming into direct contact againstmember 414. In an alternate embodiment, the thickness 406 of locknut 306from inner side 306A to outer side 306B in FIG. 21 can be the same orslightly less than the thickness 366 of anchor nut 304 from radialbearing surface 354A to open outer end 352 in FIG. 21 to enable openouter end 352 to come into direct contact against member 414. In yetanother embodiment, anchor nut 304 can be internally threaded by thread372 from open inner end 350 to open outer end 352.

IV

FIG. 29 illustrates still another embodiment of a fastener 450constructed and arranged according to the invention. Fastener 450 isuseful in forming bolted joints and includes the previously-describedbolt 302 appropriately marked as needed with its corresponding referencenumerals for reference purposes, anchor nut 454, and locknut 456configured to be repeatedly and quickly assembled and disassembled.Anchor nut 454 and locknut 456 are configured to be repeatedly assembledin FIG. 30 to form an anchor nut assembly 458 and disassembled in FIG.29 independently from bolt 452. All diameters referenced throughout thisspecification related to fastener 450 are constant.

In FIGS. 29 and 30 , anchor nut 454 is an annular block or bodyincluding open inner end 460, open outer end 462, head 464, externalthread 470, and hole 480 configured with internal thread 482. Hole 480extends through anchor nut 454 from open inner end 460 to open outer end462. Head 464 has wrench flats 466, six in this example, for nut-turnpurposes, and extends from open inner end 460 to radial bearing surface458 of head 464. Radial bearing surface 458 faces external thread 470.External thread 470 extends between radial bearing surface 458 and outerend 462, twists in a left-hand direction opposite to external thread 320of bolt 302, and is exemplary of a standard left-handed external thread.

In FIG. 30 , left-handed external thread 470 extends between radialbearing surface 458 and outer end 462 and includes minor diameter 473,major diameter 474, and pitch 475, the distance between adjacent peaksor crests of the thread. Minor diameter 473 occurs at the roots ofexternal thread 470, and major diameter 474 occurs at the crests ofexternal thread 470. External threads 320 and 470 twist in oppositedirections, as described. Accordingly, external threads 320 and 470 arecounter-threads configured to threadedly receive counter-rotatinginternally-threaded elements.

Hole 480 extending through anchor nut 454 from open inner end 460 toopen outer end 462 in FIG. 21 is internally threaded by internal thread482 from open inner end 460 to open outer end 462. Internal thread 482runs along the inside of anchor nut 454 from open inner end 460 to openouter end 462 and twists in the same right-hand direction as externalthread 320 of bolt 302 opposite to the left-hand direction of externalthread 470. Internal thread 482 includes minor diameter 483, majordiameter 484, and pitch 485, the distance between adjacent peaks orcrests of the thread. Minor diameter 483 occurs at the crests ofinternal thread 482, and major diameter 484 occurs at the roots ofinternal thread 482. Pitch 485 of internal thread 482 and pitch 325 ofexternal thread 320 of bolt 302 in FIG. 31 are identical. Minor andmajor diameters 483 and 484 of internal thread 482 correspond to therespective minor and major diameters 323 and 324 of external thread 320in FIG. 31 . Internal thread 482 and external thread 320 correspond andare the same size and have identical pitches.

Since pitch 485 of internal thread 482 and pitch 325 of external thread320 are the same, minor and major diameters 483 and 484 of internalthread 482 correspond to the respective minor and major diameters 323and 324 of external thread 320, internal thread 482 twists in the sameright-hand direction as external thread 320, and internal and externalthreads 482 and 320 are correspondingly sized, internal thread 482corresponds to and is configured to thread rotationally over and onexternal thread 320 from open outer end 462 in FIGS. 30 and 31 and offexternal thread 320 from open outer end 462. Accordingly, internalthread 482 corresponds to and is configured to thread over and onexternal thread 320.

In FIGS. 29 and 30 , locknut 456 and is an annular block configured witha threaded hole 491, including internal thread 492. Threaded hole 491extends through locknut 456 from an inner side 456A of locknut 306 to anouter side 456B of locknut 306 in FIG. 30 . Inner and outer sides 456Aand 456B of locknut 456 are radial bearing surfaces. Locknut 456 has athickness 486 from inner side 456A to outer side 456B. In FIG. 30 ,internal thread 492 runs along the inside of locknut 456 between theopposed inner and outer sides 456A and 456B and twists in the sameleft-hand direction as external thread 470 opposite to the right-handhand direction of external thread 320 of bolt 302 and internal thread482 of anchor nut 454. Internal thread 492 includes minor diameter 493,major diameter 494, and pitch 495, the distance between adjacent peaksor crests of the thread. Minor diameter 493 occurs at the crests ofinternal thread 492, and major diameter 494 occurs at the roots ofinternal thread 492. Pitches 475 and 495 are identical and somewhatsmaller than pitches 485 and 325. Minor and major diameters 493 and 494of internal thread 492 correspond to the respective minor and majordiameters 473 and 474 of external thread 470. External thread 470 andinternal thread 492 are the same size and have identical pitches. InFIG. 29 , locknut 456 has parallel and circumferentially spaced-apartwrench grooves 498 for nut-turn purposes.

Since pitch 495 of internal thread 492 and pitch 475 of external thread470 are the same, minor and major diameters 493 and 494 of internalthread 492 correspond to the respective minor and major diameters 473and 474 of external thread 470, internal thread 492 twists in the sameleft-hand direction as external thread 470, and internal and externalthreads 492 and 470 are correspondingly sized, internal thread 492corresponds to and is configured to thread rotationally over and onexternal thread 470 from open outer end 462 of anchor nut 454 in FIGS.30 and 31 and off external thread 470 from open outer end 462.Accordingly, internal thread 492 corresponds to and is configured tothread over and on external thread 470 for assembling anchor nut 454 andlocknut 456 to form anchor nut assembly 458 in FIGS. 30 and 31 .Internal threads 482 and 492 twist in opposite directions, as described,internal thread 482 in the same direction as external thread 320 of bolt302 and internal thread 492 in the same direction as external thread470. Accordingly, internal threads 482 and 492 are counter-threadsconfigured to threadedly receive counter-rotating externally-threadedelements.

In FIG. 30 , a user assembles anchor nut assembly 458 by threadinginternal thread 492 over and on external thread 470. The user threadsinternal thread 492 over and on external thread 470 by applying openouter end 462 of anchor nut 454 into threaded hole 491 from inner side456A and rotating locknut 456 in the direction of arrow C. This advanceslocknut 456 in the direction of arrow D until inner side 456A of locknut456 and radial bearing surface 468 of head 466 are juxtaposed. Locknut456 is suitably sized to extend entirely over external thread 470 frominner side 456A of locknut 456 juxtaposed with radial bearing surface468 to outer side 456B of locknut 456 at open outer end 462 in theassembly of anchor nut 454 and locknut 456 in FIG. 30 , when locknut 456is threaded on anchor nut 454. The dimension of locknut 456 from innerside 456A to outer side 456B, the thickness 486 of locknut 456 frominner side 456A to outer side 456B, is less than the dimension of anchornut 454 from radial bearing surface 468 to open outer end 462, thethickness 476 of anchor nut 454 from radial bearing surface 468 to openouter end 462. Rotating locknut 456 in the direction of arrow A oppositeto the direction of arrow C withdraws locknut 456 from radial bearingsurface 468 and off anchor nut 454 in the direction of arrow B.Accordingly, a user need only reverse the operation threading locknut456 on anchor nut 454 to separate locknut 456 from anchor nut 454.Anchor nut 454 and locknut 456 may be repeatedly assembled anddisassembled as needed.

The assembly of bolt 302 and anchor nut assembly 458 forms fastener 450in FIG. 31 . A user assembles anchor nut assembly 458 and bolt 302 byinserting bolt 302 distal end 314 first into open outer end 462 untilexternal thread 320 at distal end 314 encounters internal thread 482 atopen outer end 462. He threads internal thread 482 on external thread320 and advances anchor nut assembly 458 in the direction of arrow D byrotating bolt 302 in the direction of arrow A until internal thread 482is threaded completely on external thread 320. Locknut 456 is betweenradial bearing surface 468 and head 340, inner side 456A and radialbearing surface 468 are juxtaposed, outer side 456B and open outer end462 are juxtaposed, and external thread 320 extends through internallythreaded hole 480 from open outer end 462 to open inner end 460 andbeyond open inner end 460 to distal end 314 without interference fromlocknut 456 threaded on external thread 470 of anchor nut 454. Externalthreads 320 and 470 twist in opposite right and left directions, asdescribed. Accordingly, anchor nut 454 threaded on bolt 302 and locknut456 threaded on anchor nut 454 are counter-rotated. Rotating anchor nut454 equipped with its attached locknut 456 in the direction of arrow Aopposite to the direction of arrow C withdraws anchor nut assembly 458from external thread 320 of bolt 302 in the direction of arrow D.Accordingly, a user need only reverse the operation threading anchor nut454 on bolt 302 to separate anchor nut assembly 458 from bolt 302. Bolt302 and anchor nut assembly 458 may be repeatedly assembled anddisassembled as needed.

Fastener 450 is useful in forming bolted joint 500 in FIG. 31 ,including members 502 and 504 secured together by fastener 450, theassembly of bolt 302, anchor nut 454, and locknut 456. Members 502 and504, metal plates in this example, have registered through bores 506 and508, respectively. A user forms bolted joint 500 to secure members 502and 504 together by inserting bolt 310 distal end 314 first into andthrough bore 506 to bore 508 to seat head 340 in bore's 506 counterbore506A on one side of the bolted joint 500 and extend external thread 320outwardly from bore 508 to distal end 314 on the opposite side of boltedjoint 500. Head 340 and counterbore 506A are correspondingly shaped. Theuser installs anchor nut assembly 458 on bolt 302 to assemble fastener450 by inserting bolt 310 distal end 314 first into open outer end 462so external thread 320 at distal end 314 encounters internal thread 482.He threads internal thread 482 on external thread 320 by rotating anchornut 454 equipped with its installed locknut 456 in the direction ofarrow C. This advances anchor nut assembly 458 in the direction of arrowB until internal thread 482 is threaded completely on external thread320 and outer side 456B of locknut 456 and open outer end 456 are isconcurrently tightened directly against member 504. Since the dimensionof locknut 456 from inner side 456A to outer side 456B is less than thedimension of anchor nut 454 from radial bearing surface 468 to openouter end 462, open outer end 462 is enabled to come into direct contactagainst member 414. Bolt length 334 extends through bores 506 and 508from head 340 in counterbore 506A to external thread 320, extendingoutwardly from bore 508 to anchor nut assembly 458 and distal end 314.He alternately rotates anchor nut 454 and locknut 456 in the directionof arrow C. This alternately tightens outer side 456B of locknut 456 andopen outer end 462 of anchor nut 454 against member 504 until thedesired tension is achieved, clamping members 502 and 504 between head340 anchored in counterbore 506A on one side of bolted joint 500 andouter side 456B of locknut 456 and open outer end 462 of anchor nut 454concurrently tightened directly against member 504 on the opposite sideof bolted joint 500. With both outer side 456B of locknut 456 and openouter end 462 of anchor nut 454 concurrently tightened directly againstmember 504, locknut 456 serves its function as a locknut counter-rotatedrelative to external thread 320 of bolt 302 and internal thread 372 ofanchor nut 454 aggressively disabling bolt 302 from loosening byrotating in the direction of arrow C. Fastener 450 securing bolted joint500 is surprisingly strong and aggressive and resistant to axialfailure, shear failure, and loosening in response to vibrational andprevailing torsional forces. The user need only reverse this operationto release bolted joint 500 and withdraw fastener 450. The skilledartisan will readily appreciate that handedness of the threads describedin conjunction with fastener 450 can be reversed in alternateembodiments.

The thickness 486 of locknut 456 from inner side 456A to outer side 456Bis less than the thickness 476 of anchor nut 454 from radial bearingsurface 468 to open outer end 462. In an alternate embodiment, thethickness 486 of locknut 456 from inner side 456A to outer side 456B canbe the same as the thickness 476 of anchor nut 454 from radial bearingsurface 468 to open outer end 462.

V

The person having ordinary skill in the art will readily appreciate thatdisclosed are exemplary bolts, bolt and nut fasteners, and bolted jointsformed therewith. The various embodiments are configured to be readilyand quickly assembled and disassembled, efficient, and are structuredand arranged as disclosed to be suitably resistant to loosening inresponse to vibrational, shear and prevailing torque forces, even whenexposed to or submerged in oil or other lubricant. The variousembodiments disclosed herein are manufactured of standard materialsroutinely used in the manufacture of bolts and nuts and may beappropriately sized to relate to specific applications.

The present invention is described above with reference to illustrativeembodiments. Those skilled in the art will recognize that changes andmodifications may be made in the described embodiments without departingfrom the nature and scope of the present invention. Various changes andmodifications to the embodiments herein chosen for purposes ofillustration will readily occur to those skilled in the art. To theextent that such modifications and variations do not depart from thespirit of the invention, they are intended to be included within thescope thereof.

The invention claimed is:
 1. A bolted joint, comprising: a boltincluding a shank having a first end, a second end, an enlarged headadjacent to the second end, and a first external thread proximate to thefirst end, the bolt extending through a first member and a secondmember, respectively, between the enlarged head against the first memberand the first external thread extending outward from the second member;an anchor nut including a first open end, a second open end, a radialbearing surface between the first open end and the second open end, ahead between the radial bearing surface and the first open end, a secondexternal thread between the radial bearing surface and the second openend, a first dimension from the radial bearing surface to the secondopen end, and a first hole extending through the anchor nut from thefirst open end to the second open end, the first hole comprising a firstinternal thread; a locknut including a first side, a second side, asecond dimension from the first side to the second side, a second holeextending through the locknut from the first side to the second side,the second hole comprising a second internal thread, and the seconddimension greater than the first dimension; the first internal threadthreaded on the first external thread, the anchor nut extending outwardto the first open end from the second open adjacent to the secondmember; the second internal thread threaded on the second externalthread, the locknut between the radial bearing surface and the secondmember and tightened, the locknut extending from the first end tightenedagainst the radial bearing to the second end outboard of the second openend; and the first external thread and the first internal thread twistin a first direction, the second external thread and the second internalthread twist in a second direction different from the first direction,the first member and the second member clamped between the head againstthe first member and the second side of the locknut against the secondmember, and the locknut clamped between the radial bearing surface andthe second member.
 2. The bolted joint according to claim 1, the headcomprising wrench flats.